Evaluation of the efficacy of different techniques in removal of root canal filling during retreatment of oval shaped root canals

ABSTRACT Ecehan HAZAR. Evaluation of the efficacy of different techniques in removal of root canal filling during retreatment of oval shaped root canals.Bulent Ecevit University, Institute of Health Sciences, Department of Endodontics, PhD Thesis, Zonguldak, 2018. When initial root canal treatment fails, non-surgical treatment is prefered as the first treatment option. Studies showed that filling material can not be completely removed from the root canal system. The aim of this study is compare the efficacy of different irrigation activation methods to remove root canal obturation material from oval shaped root canals by use 3 different evaluation methods. Forty oval shaped distal canals from mandibular first molars were filled. Each distal canals were retreated with rotary retreatment files. Then all specimens were randomly assigned to one control and three experimental groups according to the activation procedures: Passive Ultrasonik Irrigation (PUI), Self Adjusting File (SAF) and XP Endo Finisher (XPF). The percentage of removed filling material was assessed by means of micro computed tomograpy and digital radiographic imaging. Root canal walls were examined and scored in three regions, apical, middle and coronal by using SEM. PUI, SAF and XPF activation in assessed micro-CT analyses improved root canal cleanliness when compared to control group (p<0.05). There was no significant difference between the PUI, SAF and XPF groups in both micro-CT analysis and digital radiographic analysis (p>0.05). When compared to control group, XPF activation technique removed more residual filling in all evaluation methods (p<0.05). There was no difference between the SAF and PUI groups in any of the evaluation methods (p>0.05). SEM evaluation showed higher scores in apical region in all groups (p<0.05). None of the activation techniques removed root canal remnants completely (p<0.05). Micro-CT provided more detailed data than digital radiography. The use of activation methods reduces the amounth of residual filling material. When XPF activation method was used, cleaner root canal walls were observed than other activation methods. Keywords: Retreatment, Passive ultrasonic irrigation, Self Adjusting File, XP Endo finisher, Micro-CT, Digital radiography, Scanning electron microscopy.